Stocks drifted slightly higher on Friday after strong earnings from retailers boosted investor confidence.

The summer vacation season sent many traders in both Europe and the U.S. on vacation, so volume was light.

The Dow Jones industrial average rose 13 points to 13,263 as of 3 p.m.

Investors liked what they heard from retailers, who reported strong second-quarter earnings — and positive outlooks. Gap Inc. shares rose 5.3 percent after it boosted its outlook and posted a 29 percent jump in net income, suggesting the operator of Gap, Old Navy and Banana Republic stores is finally on the way to a turnaround.

Shares of Ann Inc., the parent of retailer Ann Taylor, jumped 22 percent after its second-quarter profit rose 24 percent. Foot Locker rose 2 percent after quarterly profits leaped 59 percent, boosted by higher sales, cost controls and a small tax-related gain.

A few retailers did struggle. Wal-Mart fell 31 cents to $71.85, on top of a 3 percent decline a day earlier. Sears Holdings Corp. fell 2.3 percent, giving back some of Thursday’s big gain.

Facebook Inc. shares continued to fall, dropping another 65 cents to $19.22. They’ve lost almost half their value since their initial public offering. After debuting at $38 per share, the stock’s decline continued on Thursday as some of its early investors got their first chance to sell.

Retail sales boosted consumer discretionary stocks 0.4 percent, the largest gain among the 10 industry in the S&P 500.

The biggest decliner was health care, down 0.7 percent as pharmaceutical companies declined. Pfizer fell 1 percent, and Merck dropped 1.6 percent.

The stock of computer chip maker Marvell Technology Group Ltd. dropped 15 percent after a revenue decline sliced its quarterly net income by more than half. Its CEO cited a slowing economy for the trouble.

Global markets edged higher after German Chancellor Angela Merkel gave a new pledge of support for the euro. On Thursday she said that “we feel committed to do everything we can to maintain the common currency.” Germany is Europe’s economic powerhouse, so its support is critical to the euro’s survival.